What to look for in a new car

Car experts from NRDC demystify the art of car buying.

Picking a new car is never easy, but now with electric plug-in vehicles arriving, clean diesel options available and the unstable economy (not to mention the price of gas), the decision is more fraught than ever. I spoke with Deron Lovaas, NRDC's federal transportation policy director, and Luke Tonachel, vehicle analyst for NRDC, about their suggestions to ease car-purchasing decisions.

Simple Steps: In terms of the environment, which are the most important measurements when comparing cars? MPG, EPA’s air pollution score and greenhouse gas emissions rating, ACEEE’s green score, any others?

Deron Lovaas: If people care about the environment, then EPA’s emissions ratings are going to be most important (you can see listings at epa.gov/greenvehicles and fueleconomy.gov). Grams CO2 per mile (or gCO2/mi) is going to be more important than MPG. The standards are now joint EPA and DOT and so the EPA should make it more transparent to consumers what the g/mi rating is for any given automobile. Fuel consumption is a decent proxy for GPM, but there are other factors such as air conditioning which can decrease carbon emissions without affecting MPG. The ACEEE green score is also a terrific resource.

Do you have any transmission preferences beyond manual vs. automatic — do things like “electronically controlled automatic overdrive” or “automatic continuous variable transmission” make a difference for fuel efficiency?

Luke Tonachel: Consumers should look at the overall performance of the vehicle and choose the model that meets their needs with the lowest carbon pollution. Cars are designed as a system and looking at just one aspect would be simplistic. In some cases, a model with a manual transmission will have lower emissions than other, similarly-equipped models. In other cases, advanced automatic transmissions (with more gears, for example) can save more fuel and cut emissions.

How much attention do you pay to torque and/or horsepower? The Prius has a low torque but that hasn’t seemed to deter its fervent owners.

Lovaas: For the past few decades, cars every year have technically become more fuel efficient at the rate of 1 percent to 2 percent per year, but that’s been trumped by other attributes: more power and more weight. So there is a bit of a tradeoff there. Automakers have the know-how to design vehicles that maintain today’s power while cutting fuel use. The recently announced EcoBoost technology from Ford is a good example. Ford is using smaller, gasoline direct-injection engines with turbocharging to cut fuel use without losing acceleration. Electric-drive cars can also have excellent torque because electric motors don’t take a lot of time to spin up to full power.

What about diesels? Are there enough options now to make them competitive across size classes?

Lovaas: New designs with better pollution control mean that diesels are an option, but it’s unclear how competitive they will be in the U.S., despite the advantages of their fuel economy. Diesels offer substantial gains when it comes to highway fuel economy and new technologies offer answers to prevent higher emissions of ozone-forming NOx and particulates. But diesel took a black eye in the '70s from the sootiness which meant the U.S. fleet is predominantly gasoline-powered.

Diesels may appeal to folks that do a lot of long-distance travel, and VW and BMW are predicting robust sales. Diesels, however, will have to compete with continual improvements from conventional and hybrid gasoline-fueled vehicles.

We’ve been waiting years for the Chevy Volt, Nissan LEAF and other long-range, semi-affordable plug-in electric vehicles — should their eventual release be a consideration when choosing whether to lay down a similar amount for a new car now?

Tonachel: Indeed, plug-in cars are coming! Both the Volt and LEAF are scheduled to be in showrooms late this year and they will be followed within a year or two by offerings from such makers as Toyota, Ford, the upstart Coda Automotive and others. They are definitely worth consideration.

In general, electric vehicles are the cleanest options, emitting less global warming pollution from the power plant than the cleanest hybrid emits from its tailpipe. Having said that, how clean an electric vehicle is will depend on how clean your power plants are; areas that depend more on dirty coal plants, like the Midwest, will see less pollution-reduction benefits than areas like California, which has adopted many policies to force utilities to clean up their power plants. In the worst case, an EV charged up solely on electricity generated from old coal plants is about as a clean as a good hybrid, like a Toyota Prius. Simply put, when it comes to electric cars, cleaner power plants means cleaner cars.

Plug-in vehicles will also be more expensive but federal (and in some cases state) incentives will significantly bring down the cost. You should check what’s available where you live.

Finally, in the U.S., the perception has long been that fuel-efficient cars are less safe than steel behemoths, SUVs and the like. What do the front and side crash tests tell us?

Lovaas: Pretty recent front and side crash tests tell us that design can trump weight thanks to new, more durable, lightweight material and thanks to crumple zones in the front of the car, more air bags, sturdier cages around the passengers and better design. Recent trends have shown that consumers are moving away from the heaviest, gas-guzzling trucks in favor of cars and crossover vehicles based on lighter body designs. One of the benefits of the increasing fuel-economy standards will mean that consumers will have more choices of "right-sized" vehicles that meet their needs without so much weight. The data is clear that we can save lives if we reduce the incompatibility of vehicles on the road. If the larger pickups and SUVs are involved in a crash, there’s a good chance that the driver and passengers of the other car will be harmed. The very largest of the light trucks will no longer be on the road, and the incompatibility of those vehicles has literally been a killer.

Honda has made it clear that design can trump the behemoth factor, because the car is literally designed to sacrifice itself. And there’s no getting beyond the fact that driving behavior and basic habits like buckling seatbelts help determine the safety of driving on the road.